JPH09161243A - Multilayered magnetoresistive film and magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a multilayered film showing a high change rate of the magnetoresistance effect by using a material having the face centered cubic structure and high electric resistance as a crystal system controlling layer. SOLUTION: A Si (100) single crystal is used as a substrate 11. Hf is used for a crystallinity controlling layer 12 and a Cu(50at.%)-Ni alloy layer is used for a crystal system controlling layer 13. A Fe(40at.%)-Mn alloy is used for an antiferromagnetic layer 14. A Ni(16at.%)-Fe(18at.%)-Co alloy is used for a magnetic layer 15 and a magnetic layer 19. The Co is used for a magnetic layer 16 and a magnetic layer 18. Cu is used for a nonmagnetic layer 17. In the obtd. multilayered film, the crystal system controlling layer 13 has high electric resistivity and an electric current hardly passes through the layer 13 so that a high change rate in the magnetoresistance effect can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer magnetoresistive effect film having a high magnetoresistive effect, a magnetoresistive effect element using the same, a magnetic head and a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art As the magnetic recording density increases, a material having a high magnetoresistive effect is required as a magnetoresistive effect material used for a reproducing magnetic head. So, Physical Review B, Vol. 43, Vol. 1
No. 1297-1300, "Giant Magnetoresistance Effect in Soft Magnetic Multilayer Films"
In Soft Ferromagnetic Multilayers), a method has been devised in which two magnetic layers are separated by a non-magnetic layer and an exchange bias magnetic field from an antiferromagnetic layer is applied to one magnetic layer.

In such a multilayer film, normally, the Chinese Journal of Applied Physics Jpn. J.
Appl. Phys., Vol. 33, No. 1A, pp. 133-137, "Fe-M Using Various Buffer Layer Materials".
Magnetoresistance and Crystal Orientation of n / Ni-Fe / Cu / Ni-Fe Sandwich "(Magnetoresistance and Prefer)
red Orientation in Fe-Mn / Ni-Fe / Cu / Ni-Fe Sandwiches
In order to control crystallinity, Ti, Zr, H
A multilayer film is formed on the buffer layer made of metal such as f, Nb, and Ta. This is because the magnetic layer and the nonmagnetic layer having the face-centered cubic structure of the multilayer film have the (111) plane orientation, and the Mn-based antiferromagnetic layer formed thereon has the face-centered cubic structure. Many Mn antiferromagnetic layers exhibit antiferromagnetism at room temperature only when they have a face-centered cubic structure.

Such a multilayer film is usually formed from the substrate side.
The crystallinity control layer, the magnetic layer, the nonmagnetic layer, the magnetic layer, and the antiferromagnetic layer are formed in this order. However, depending on the structure of the magnetoresistive effect element, it may be necessary to sequentially form the crystallinity control layer, the antiferromagnetic layer, the magnetic layer, the nonmagnetic layer, and the magnetic layer from the substrate side. However, even if the Mn-based antiferromagnetic layer is formed directly on the crystallinity control layer made of a metal such as Ti, Zr, Hf, Nb, or Ta, Jpn. J. Appl. Phys., Vol. 33, No. 10, pp. 5734-5738, "3 layers of N
Magneto-resistance Effects in Spin-Valve
Multilayers Including Three Ni-Fe-Co Layers), the Mn-based antiferromagnetic layer does not have a face-centered cubic structure and does not exhibit antiferromagnetism at room temperature. Therefore, as in the above-mentioned document, a crystalline control layer made of Cu is formed on the crystalline control layer, an Mn antiferromagnetic layer is formed on the crystalline control layer, and an Mn antiferromagnetic layer is formed. Face-centered cubic structure. Also,
This structure is also used in a spin valve having three magnetic layers.

[0005]

[Problems to be Solved by the Invention] However, Jpn.
J. Appl. Phys., Volume 33, No. 10, 5734-573.
As described on page 8, if Cu is used for the crystal system control layer, a high magnetoresistance change rate cannot be obtained. It is considered that this is because the electric resistivity of Cu is as low as about 9/10 ⁸ Ωm and the current flowing through the multilayer film is shunted to the Cu layer.

An object of the present invention is to provide a method for solving the decrease in the magnetoresistive change rate in a high magnetoresistive effect multilayer film for a magnetoresistive effect type head.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies on a magnetoresistive effect element using a multilayer magnetic film in which magnetic layers and nonmagnetic layers having various materials and film thicknesses are laminated, and as a result, By using a material having a high electric resistivity as the crystal-based control layer, it was found that a shunt of current to the crystal-based control layer was reduced and a high magnetoresistance change rate was obtained, and the present invention was completed. I arrived.

However, for the purpose of controlling the crystal shape of the Mn-based antiferromagnetic layer, the crystal-based control layer must have a face-centered cubic lattice. Further, it is preferable that the crystalline control layer has a higher electric resistivity than the magnetic layer forming the main part of the multilayer film. Under these conditions, the crystalline control layer is Cu-
Ni-based alloys are preferred.

As described above, by using a material having a face-centered cubic lattice as the crystal-based control layer, the Mn-based antiferromagnetic layer can have a structure having antiferromagnetism at room temperature.
Further, by increasing the electrical resistivity of the crystal system control layer, it is possible to reduce the shunt of the current to the crystal system control layer,
The magnetoresistance change rate of the multilayer film can be increased.

The multilayer magnetoresistive effect film according to the present invention is suitable for a magnetoresistive effect element, a magnetic field sensor, a magnetic head and the like. Further, by using the magnetic head, a high-performance magnetic recording / reproducing apparatus can be obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 shows a sectional structure of a multilayer film according to an embodiment of the present invention.

An ion beam sputtering method was used for manufacturing the multilayer film. The ultimate vacuum is 3/10 ⁵ Pa, and the Ar pressure during sputtering is 0.02 Pa. Also,
The film formation rate is 0.01 to 0.02 nm / s. As the substrate 11, a single crystal of Si (100) was used. As the crystallinity control layer 12, Hf with a thickness of 5 nm was used. As the crystal system control layer 13, Cu-50 at% Ni having a thickness of 5 nm is used.
An alloy layer was used. For the antiferromagnetic layer 14, a Fe-40 at% Mn alloy having a thickness of 10 nm was used. The magnetic layer 15 and the magnetic layer 19 have N thicknesses of 3 nm and 9 nm, respectively.
An i-16 at% Fe-18 at% Co alloy was used. Co having a thickness of 2 nm and 1 nm was used for the magnetic layer 16 and the magnetic layer 18, respectively. The nonmagnetic layer 17 is made of Cu having a thickness of 2.5 nm.

As a comparative example, a multilayer film using a Cu layer having a thickness of 5 nm was also formed as the crystal system control layer 13.

The rate of change in magnetoresistance of the multilayer film of the above comparative example was 4.8%. On the other hand, the magnetoresistive change rate of the multilayer film of the present invention was 5.5%.

In order to measure the electrical resistivity of the crystal system control layer 13 used in the present invention, that is, the Cu-50 at% Ni alloy layer, a Cu-50 at% Ni alloy film having a thickness of 50 nm was formed. The electrical resistivity of this alloy film was 65/10 ⁸ Ωm. The electric resistivity of Cu with a thickness of 50 nm is 9 /
It was 10 ⁸ Ωm. From these results, it is considered that the multilayer film of the present invention has a high magnetoresistive change rate because the electric resistance of the crystalline control layer is high and it is difficult for current to flow in the crystalline control layer.

The structure of the present invention can also be applied to a multilayer film including three magnetic layers. That is, as shown in FIG.
A crystallinity control layer 22 made of Hf having a thickness of 5 nm is formed thereon, and a crystal system control layer 23 made of a Cu-50 at% Ni alloy having a thickness of 5 nm and Fe-40 at% having a thickness of 10 nm are further formed.
An antiferromagnetic layer 24 made of a Mn alloy was formed. Magnetic layer 2
5 and the magnetic layer 33 have a thickness of 3 nm of Ni-16 at%.
An Fe-18 at% Co alloy was used. For the magnetic layer 29, a Ni-16 at% Fe-18 at% Co alloy having a thickness of 8 nm was used. Co having a thickness of 2 nm was used for the magnetic layer 26 and the magnetic layer 32. Co having a thickness of 1 nm was used for the magnetic layers 28 and 30. Further, for the nonmagnetic layer 27 and the nonmagnetic layer 31, Cu having a thickness of 2.5 nm was used. Also,
The antiferromagnetic layer 34 also has a thickness of 10 nm of Fe-40 at% M.
An n alloy layer was used. The rate of change in magnetoresistance of this multilayer film is 7.
It was 5%.

In this embodiment, Cu- is used as the crystal system control layer.
A 50 at% Ni alloy layer was used, but for the purpose of the present invention, M
If the n-type antiferromagnetic layer has a face-centered cubic structure and the material has a high electric resistivity, it can be used as a crystal-based control layer. From the viewpoint of current shunting, a material having a higher electrical resistivity than the magnetic layer, which is the main component of the multilayer film, is preferable.

In this embodiment, Hf is used as the crystallinity control layer 12 or 22, but Ti, Zr, V, N is used.
Metal selected from b, Ta, or Ti, Zr, H
Even if an alloy of f, V, Nb, and Ta, or an alloy containing the above-mentioned metal as a main component is used, the crystal orientation of the crystal system control layer becomes (111), and Mn formed on the crystal system control layer.
The system antiferromagnetic layer can have a face-centered cubic structure.

In this embodiment, the magnetic layer is made of Ni.
A laminated body of a —Fe—Co based alloy layer and a Co layer was used, and the magnetic layer in contact with the non-magnetic layer was the Co layer. This is to increase the magnetoresistance change rate of the multilayer film. But,
Especially when the soft magnetic characteristics of the magnetic layer are emphasized, it is preferable to use a Ni—Fe based alloy layer or a Ni—Fe—Co based alloy layer as the magnetic layer. Further, instead of the Co layer, an alloy layer containing Co as a main component can be used.

In this embodiment, the Fe-Mn alloy layer is used as the antiferromagnetic layer containing Mn, but other Mn alloys may be used. Other Mn-based alloys include Mn-Ir-based alloy layers, Co-Mn-based alloy layers, Co-Mn-Pt-based alloy layers, Ni-Mn-based alloy layers, Ni-Mn-Cr-based alloy layers,
A Cr-Mn-based alloy layer, a Cr-Mn-Pt-based alloy layer, etc. are preferable.

In this embodiment, the nonmagnetic layer is made of C
Although u was used, similar results can be obtained by using Au or Ag, which has a low electric resistivity. However, when a 3d transition metal is used for the magnetic layer, the non-magnetic layer is preferably Cu from the viewpoint of matching the Fermi surface with the magnetic layer.

Example 2 As described above, a material having a face-centered cubic structure and a high electric resistivity can be used as the crystal-based control layer. However, for the purpose of controlling the crystal shape of the Mn-based antiferromagnetic layer, the crystal-based control layer is Mn.
It is preferable that the lattice constant is substantially the same as that of the antiferromagnetic layer. Cu and Ni have a face centered cubic lattice and, in addition, these alloys have high electrical resistivity. From such conditions,
The crystal system control layer is preferably a Cu-Ni system alloy.

FIG. 3 shows the Ni concentration dependence of the electrical resistivity of a Cu-Ni alloy film having a thickness of 50 nm. The sample was formed in the same manner as in Example 1. As shown in the figure, the Ni concentration is 5
The electric resistivity of the Cu—Ni based alloy film becomes high near 0 at%. When the Ni concentration is 30 to 75 at%, Cu-N
The electrical resistivity of the i-based alloy film is 40/10 ⁸ Ωm or more. Further, when the Ni concentration is 46 to 59 at%, Cu-N
The electrical resistivity of the i-based alloy film is 60/10 ⁸ Ωm or more.

(Example 3) A magnetoresistive effect element using the multilayer film of the present invention was formed. In this example, the multilayer film having the three magnetic layers described in Example 1 was used. FIG. 4 shows the structure of the magnetoresistive effect element. The magnetoresistive effect element includes a multilayer magnetoresistive effect film 51, an electrode 52, a shield layer 53,
It has a structure sandwiched by 54. When a magnetic field was applied to the magnetoresistive effect element and a change in electric resistivity was measured, the magnetoresistive effect element using the multilayer magnetoresistive effect film of the present invention was found to be 1.
The applied magnetic field of about 6 kA / m (20 Oe) showed a magnetoresistance change rate of 7.1%. Further, the reproduction output of the magnetoresistive effect element of the present invention was 3.4 times that of the magnetoresistive effect element using the Ni-Fe single layer film.

(Embodiment 4) FIG. 5 shows the structure of a magnetic head manufactured by using the magnetoresistive effect element described in Embodiment 3. This figure is a perspective view when a part of the recording / reproducing separated type head is cut. The portion sandwiched between the multilayer magnetoresistive effect film 61 by the shield layers 62 and 63 functions as a reproducing head,
The lower magnetic pole 65 and the upper magnetic pole 66, which sandwich the coil 64, function as a recording head. Further, the electrode 68 is made of Cr / C.
A multi-layered material called u / Cr was used.

The manufacturing method of this head will be described below. Al
_A sintered body mainly composed of ₂ O ₃ .TiC was used as a slider substrate 67. Shield layers 62 and 63, recording magnetic poles 65 and 6
A Ni—Fe alloy formed by a sputtering method was used for 6. The thickness of each magnetic film was as follows. The upper and lower shield layers 62 and 63 were 1.0 μm, the lower magnetic pole 65 and the upper part 66 were 3.0 μm, and Al ₂ O ₃ formed by sputtering was used as a gap material (not shown) between the layers. The thickness of the gap layer was 0.2 μm between the shield layer and the magnetoresistive element, and 0.4 μm between the recording magnetic poles. Further, the distance between the reproducing head and the recording head was set to about 4 μm, and this gap was also formed of Al ₂ O ₃ (not shown). Cu having a film thickness of 3 μm was used for the coil 64.

When recording / reproducing was performed with the magnetic head having this structure, a reproducing output 3.2 times higher than that of the magnetic head using the Ni--Fe single layer film was obtained. This is probably because the magnetic head of the present invention used a multilayer film exhibiting a high magnetoresistance effect.

The magnetoresistive effect element of the present invention can also be used in a magnetic field detector other than the magnetic head.

(Embodiment 5) Using the magnetic head of the present invention described in Embodiment 4, a magnetic disk device was manufactured. The structure of the device is shown in FIG. For the magnetic recording medium 71, a material made of a Co—Ni—Pt—Ta alloy having a residual magnetic flux density of 0.75T was used. The track width of the magnetic head 73 is 2.5 μ
m. Here, 74 is a head drive unit, and 75 is a reproduction signal processing system. Since the magnetoresistive effect element of the magnetic head 73 has a high reproduction output, a high-performance magnetic disk device that does not impose a burden on signal processing was obtained.

[0030]

EFFECT OF THE INVENTION A multilayer film having a structure of magnetic layer / non-magnetic layer / magnetic layer / Mn-based antiferromagnetic layer / crystalline control layer / crystallinity control layer / substrate, or Mn-based antiferromagnetic layer / magnetic In a multilayer film having a structure of layer / nonmagnetic layer / magnetic layer / nonmagnetic layer / magnetic layer / Mn-based antiferromagnetic layer / crystalline control layer / crystallinity control layer / substrate, the electrical resistivity as a crystalline control layer And a material having a face-centered cubic structure was used. With this structure, the Mn-based antiferromagnetic layer has a crystal structure that exhibits an antiferromagnetic layer at room temperature, and because the electric resistivity of the crystal-based control layer is high, it is difficult for current to flow in the crystal-based control layer. As a result, a multilayer film showing a high magnetoresistance change rate could be obtained. Furthermore, the multilayer magnetoresistive effect film is suitable for a magnetoresistive effect element, a magnetic field sensor, a magnetic head, and the like. Further, by using the magnetic head, a high performance magnetic recording / reproducing device can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a multilayer magnetoresistive effect film having two magnetic layers of the present invention.

FIG. 2 is a sectional view of a multilayer magnetoresistive effect film having three magnetic layers of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between Ni concentration and electric resistivity of a Cu—Ni alloy film.

FIG. 4 is a perspective view showing the structure of a magnetoresistive effect element using the multilayer magnetoresistive effect film of the present invention.

FIG. 5 is a perspective view showing the structure of the magnetic head of the present invention.

FIG. 6 is an explanatory diagram of a magnetic disk device of the present invention.

[Explanation of symbols]

11 ... Substrate, 12 ... Crystallinity control layer, 13 ... Crystal system control layer, 14 ... Antiferromagnetic layer, 15, 16, 18, 19 ... Magnetic layer, 17 ... Nonmagnetic layer.

Claims (13)

[Claims] 1. A crystallinity control layer, a crystal system control layer, an antiferromagnetic layer containing Mn, a magnetic layer containing Ni and Fe, a non-magnetic layer,
In a multilayer film formed by sequentially forming magnetic layers containing Ni and Fe, the crystal system control layer has a face-centered cubic lattice,
The crystalline control layer has a higher electrical resistivity than the magnetic layers containing Ni and Fe, and the electrical resistivity of the multilayer film changes depending on the relative angle formed by the magnetizations of the magnetic layers sandwiching the non-magnetic layer. Multilayer magnetoresistive film. 2. A crystallinity control layer, a crystal system control layer, an antiferromagnetic layer containing Mn, a magnetic layer containing Ni and Fe, a nonmagnetic layer,
Magnetic layer containing Ni and Fe, non-magnetic layer, Ni and F
In a multilayer film in which a magnetic layer containing e and an antiferromagnetic layer containing Mn are formed in this order, the crystal system control layer has a face-centered cubic lattice, and the crystal system control layer has an electrical resistivity of Ni and Fe. A multi-layered magnetoresistive effect film which is higher than a magnetic layer containing the above-mentioned two non-magnetic layers and in which the electrical resistivity of the multi-layered film changes depending on the relative angle formed by the magnetizations of the magnetic layers sandwiching the two non-magnetic layers. 3. The crystallinity control layer according to claim 1, wherein the crystallinity control layer contains a metal selected from Ti, Zr, Hf, V, Nb, and Ta, an alloy of the above metals, or a metal as a main component. A multi-layered magnetoresistive film that is an alloy. 4. The multilayer magnetoresistive effect film according to claim 1, wherein the crystal system control layer is a Cu—Ni system alloy. 5. The multilayer magnetoresistive effect film according to claim 4, wherein the Ni concentration in the Cu—Ni alloy is 30 to 75 at%. 6. The multilayer magnetoresistive effect film according to claim 4, wherein the Ni concentration in the Cu—Ni alloy is 46 to 59 at%. 7. The multilayer structure according to claim 1, 2, 3, 4, 5 or 6, wherein the magnetic layer containing Ni and Fe is a Ni—Fe alloy layer or a Ni—Fe—Co alloy layer. Magnetoresistive film. 8. The magnetic layer containing Ni and Fe according to claim 1, wherein the magnetic layer containing Ni and Fe is a Ni--Fe alloy layer, or a Ni--Fe--Co alloy layer and Co.
A multilayer magnetoresistive effect film which is a laminated body of a layer or an alloy layer containing Co as a main component, wherein the Co layer or an alloy layer containing Co as a main component is in contact with the nonmagnetic layer. 9. The antiferromagnetic layer containing Mn according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein an Fe—Mn based alloy layer, a Mn—Ir based alloy layer, and a Co—Mn layer. System alloy layer, C
o-Mn-Pt alloy layer, Ni-Mn alloy layer, Ni-
Mn-Cr alloy layer, Cr-Mn alloy layer, Cr-Mn
-A multilayer magnetoresistive film which is an alloy layer selected from Pt-based alloy layers. 10. The method of claim 1, 2, 3, 4, 5, 6, 7, 8
Alternatively, a magnetoresistive effect element including the multilayer magnetoresistive effect film described in 9. 11. A magnetic head including the magnetoresistive effect element according to claim 10. 12. A composite magnetic head in which the magnetoresistive effect element according to claim 11 and an inductive magnetic head are combined. 13. A magnetic recording / reproducing apparatus using the magnetic head according to claim 11 or 12.